Conversion of hydrocarbons



M. M. MARISIC CONVERSION OF HYDROCARBONS Sept. 18, 1945.

Filed April 22, 1945 3 Sheets-Sheet 1 INVENTOR MILTON MMAR/J/C BY? ATTORNEY m9 MU GEL PELLETS PROCESSING Sept. 18, 1945. M. M. MARISIC CONVERSiON OF HYDROCARBONS Filed April 22, 1943 3 Sheets-Sheet 3 R O T N E V m MIL TON M. MAR/51C lQwu/z 414 a ATTORN EY Patentcilsept- 18,1945

2,884,943 CONVERSION 0! BYDBOOABBONS Milton M. Marisic,

Socony-Vacuum Woodbury, N. 1., assignor to Oil Company, Incorporated, a

corporation or New York Application April 22, 1943, Serial No. 483,993 ii Claims. (Cl. 196-152) This invention is directed to catalytic conversion oi hydrocarbons and is specifically concerned with the provision of a process utilizing a synthetic catalyst which may be of conventional chemical composition but is properties rendering it peculiarly suitable to the purpose. This application is a continuation-inpart or my prior copending application Serial No. 461,454, tiled October 9, 1942.

It is known that many operations for the conversion of hydrocarbon materials to other hydrocarbon materials of diilering physical and/or chemical properties may be carried out catalytically. Most of these are carried out by contacting the hydrocarbon, usually in vapor .iorm and at high temperature, with a contact mass composed of particles which themselves have a catalytic eflect, or which are impregnated with or act as a support for other catalytic material of a nature appropriate to the result desired. Such operations may contemplate, for example, the conversion of hydrocarbons of high boiling point to those oi lower boiling point, or the polymerization of light or gasous hydrocarbons to hydrocarbons of higher boiling point. Other operations of like nature are catalytic dehydrogenation, hydrogenation, polymerization, alkylation, reforming, aromatizatlon, desuliurizing, partial oxidation and similar conversions of hydrocarbon materials. The method of operation herein disclosed is applicable to all such conversions. 0! these operations, the vapor phase cracking of heavy hydrocarbons to gasoline is typical, and this specification will hereinafter discuss such operations as exemplary, without, however, intending to be limited thereby or thereto except by such limits as may appear in the claims.

Such catalytic processes generally make use of reaction chambers containing a fixed body of catalyst or contact mass, through which the reaction mixture is passed, and in which, after the reaction has slowed down to an uneconomic point, the contact mass is regenerated in situ. Such processes are not continuous, and only attain continuity by the provision oi numerous re-,

action chambers which are alternately placed on stream and on regeneration. Likewise, it is difiicult to maintain constant quantity and quality oi product without numerous chambers and inpossessed of physical tricate scheduling, due to the progressively decreasing activity of the catalyst. This same feature, with apparatus limitations, prevents, to a degree. the use of catalyst, at a uniform high efiiciency level. Most of these difllculties may be avoided by the use of a method wherein the catlyst or contact mass is handled continuously as well. The catalyst is particularly well adapted to such a process, although advantages over previous catalysts are noted in stationary bed operations.

This invention has for its preierred object the use of a catalyst for a process of hydrocarbon oil conversion wherein a continuously moving stream of hydrocarbon oil is contacted with a continuously moving stream of catalyst for the accomplishment 01' conversion, in which the catalytic material is used only at a high level of emciency, and in which the catalytic material is continuously regenerated and returned to the conversion step, both operations being conducted under controlled conditions.

In such operations, the term "gel has been rather loosely applied to include both true gels and gelatinous precipitates. In forming pellets of either, the gel or precipitate has been caused to form completely and then subjected to suitable operation for the formation of particles. These have not been particularly satisfactory because the particles obtained are not resistant to losses by shock breakage and abrasion. The common operations includ breaking a mass oi gel to fragmentary particles and screening to separate particles oi desired size. This results in the production oi a considerable amount of fines which are a loss since they cannot be re-used in the same catalytic equipment. In some cases, the wet gel is molded. This requires expensive molding equipment and costly cleaning of molds. It is also proposed (Reissue Patent 21,690) to separate the mass into two parts, one of which is dried and crushed and the other used wet to bind the crushed portion in a molding operation which involves the usual obiections to molding.

The present catalyst is prepared by a method which eliminates the heretoiore necessary step of converting formed gel masses into a usable term by some type oi pelleting operation. Another feature is that the gel contact masses are produced in spherical and/or spheroidal shapes.

This form is ideal for any process in which a contact bed is utilized, whether it be of the stationary or the moving (or flowing) type of bed. spherically-shaped particles can pack only in a uniform manner, hence, channeling of vapors or fluids flowing through this type of bed is impossible. For an operation in which a moving (or flowing) contact bed is employed, pellets of a spherical shape afl'ord unique flow characteristics. The present catalyst is exceptionally hard and presents novel advantages over previously known catalysts apart from the spheroidal shape of the preferred form. This hardness is retained by particles produced by crushing the spheroids and, hence, broken pieces may b used within the scope or the invention as hydrocarbon conversion catalyst.

The above-mentioned process of forming the pellets involves continuously contacting within an enclosed mixing chamber such as an injector or nozzle mixer, streams of reactant solutions of such concentrations and proportions that no gelation occurs within the mixer, but only at some predetermined time after leaving the mixer, and under such conditions of flow that each stream is completely and uniformly dispersed within and throughout the other at the instant of contact. The resulting colloidal solution is elected from the mixer through an orifice or orifices of suitable size so as to form globules of the solution which are introduced into a fluid medium where the globules of the colloidal solution set to a gel before they pass out of that medium. The fluid medium may be any liquid or combination of liquids which is immiscible with water such as,

for example, petroleum naphtha, kerosene, hydrocarbon oils, etc. Pellets may also be formed by a process analogous to spray drying wherein the gelable solution is sprayed into a drying tower under conditions such that the particles of the solution set to a gel and are dried to about to water content. This process is claimed in my application Serial No. 461,453, filed October 9, 1942.

There are two alternative methods of liquid phase operation which are dependent upon the density of the fluid employed. when the density of the fluid is lower than that of water, the fluid is supported over a layer of water and the colloidal solution from the mixer is introduced at the top or the column or fluid; the height of the latter and the gelation time being adjusted so that gelation occurs within the fluid and before the globose particles reach the water surface. For a fluid more dense than water, the procedure is reversed; the colloidal solution is elected into the bottom of the fluid, the globules rise up through the fluid, gel and pass into a layer of water which conducts the gel away for processing.

The shapes of the formed gel are dependent upon the rate at which the globules of the colloidal solution travel through the water-immiscible liquid: while the rate of movement of the globules depends upon the relative density and viscosity of the fluid medium employed. It the latter medium has a low viscosity and a density far removed from that of the colloidal solution, the globules of the latter solution will travel rapidly. hence, the gel pellets will assume flat or disc-like shapes. Examples of liquids in which pellets of this type may be produced are benzene, carbon tetrachloride, or petroleum naphtha. A waterimmiscible fluid medium having a high viscosity or a density close to that of the colloidal solution will eflect slow movement oi. the globules or the letter solution and thus form spherically-shaped gel pellets. It is apparent from the above description that gel pellets of any shape, varying from flat-like discs to perfect spheres, may be manufactured by choice of a water-immiscible fluid medium having the proper density and viscosity.

The success of this process is due to the tact that the gelation time for a large number of materials can be controlled Very accurately.

I have studied the preparation of many gels in which silica is the predominant component and round that the gelation time can be controlled so that the invention described above may be utilized in their preparation. The following is a list of the gels I have prepared by the methods described herein: silica gel, silica-alumina, silica-stannic oxide, silica-eerie, sillca-thorla, silica zirconia, silica-alumina-thoria, silica-alumina zirconia, sillca-alumina-stannic oxide, silica-aluminaoeria. Further, the methods described herein may be extended to the preparation of many other types of gels.

The time of gelation is dependent upon temperature, pH and concentrations of reactants. The higher the temperature, the shorter the time of gelation. At fixed concentrations of reactants the gelation time increases with decrease in pH provided the pH is within limits. when the temperature and pH are constant, the gelation time decreases as the reactant solutions are made more concentrated. Considerations controlling gelation time are discussed in detail in my copending application Serial No. 461,455, filed October 9, 1942.

Briefly, the process utilizes a catalyst pellet of generally rounded outline having uniform porosity, a hard surface and unusually high crushing strength. These pellets are better suited to stationary bed operation than conventional molded catalyst pellets because of their high resistance to breakdown in transportation and use: but their advantages are achieved to a very high degree when used in continuous processes involving constant exposure to forces tending to abrade and crush the pellets.

Other objects and advantages will be apparent from the detailed description below when considered in connection with the attached drawings wherein:

Figure 1 shows apparatus for use in preparing the catalyst;

Figures 2 and 3 show modified types of mixing nozzles for the apparatus of Figure 1;

Figure 4 is a modified type of apparatus for forming the pellets;

Figure 5 is an illustration in vertical section of apparatus for continuous catalytic conversion of hydrocarbons;

Figure 6 is a diagrammatic showing of a plant unit including auxiliaries for the process;

Figure I is a diagrammatic illustration of contacting apparatus of the type wherein the catalyst is suspended in the reactant gases; and

Figure 8 is a section on line 8-8 of Figure 7.

Referring to Figure l, a mixing nozzle, indicated generally at M, is mounted at the top of a column of water-immiscible fluid in a tank ll. At the bottom of, tank I l is a layer of water which forms an interface I! with the column of said fluid. Water is continuously supplied through inlet II and withdrawn through outlet ll. The interface at I! is maintained by properly adjusting the height of conduit 8 in correlation with the density of the fluid medium and the rate at which water is supplied at i I. Vent l5 prevents siphonaasaosa in: action. The flow of water carries away the gel pellets through outlets M and I to suitable washing and treating stages. The water in which the pellets are carried away is itself a washing medium and may include any desired treating material to act as a treating stage.

The colloidal solution from which the pellets are formed is made up and admitted to the column of fluid by the mixing nozzle l0. Preferably, the apparatus will include a plurality of nozzles II in order to increase the capacity oi. the unit, but only one is shown here for purposes of simplicity. The nozzle includes means for completely dispersing two solutions in each other and admitting a continuous stream of the so-formed colloidal solution below the surface it of the water-immiscible fluid. wherein the stream of the colloidal solution breaks up into globules. The colloidal solution or globules thereof may be dropped on the surface of the fluid. but this tends to break them and impairs control over pellet size obtained by injecting the colloidal solution under the surface of the liquid. It must be borne in mind that considerable shrinkage takes place, not only by syneresis, but also during drying and processing. Control of globule size must take into account this shrinkage.

The size of the globules is controlled by the rate at which the colloidal solution flows through the nozzle orifice and the dimensions of the latter. A simple modification in controlling the size of the globules is the introduction of a baflle just outside of the nozzle mixer and in the stream of the colloidal solution. Furthermore, sizin is a matter of relative densities and viscosities of the colloidal solution and water-immiscible liquid.

In the mixing nozzle Ill, solutions to be mixed are metered accurately and then admitted through lines I! and It to a chamber which has a. rotor ll rotated by shaft 20 at a speed of at least about 1700 R. P. M. from a source or power not shown. The rotor I! is constructed from a rectangular bar of metal whose edges are rounded off in such manner that the walls of the mixing chamber serve as a guide for them. The rounded edges of the rotor are grooved; thus, efllcient dispersion of both solutions in each other is maintained and gel formation is prevented in the mixing nozzle. The rotor may be fluted in any suitable manner or provided with other inequalities of surface to increase agitation in the mixing zone. Helical grooves for such purpose are shown on the rotor II of the modified form of mixing nozzle illustrated diagrammatically in Figure 2. The best operation of the mixing nozzle is realized when the rates of the reactant solutions are so high that the time the latter solutions spend in the mixing chamber is only a very small fraction of the gelation time.

A further modification is the extremely simple mixer of Figure 3 wherein the rotor 22 is merely a shaft which may be fluted, grooved, etc.

Another modification that may be applied to any of the mixing nozzles illustrated in Figures 1, 2 and 3 is to provide means for injecting air into the solutions admitted to the mixing chamber or to the mixing nozzle itself. By this means, hydrogel pellets are obtained which contain numerous small bubbles of air which serve to make the processed dry gel less dense in nature and more porous.

The apparatus of Fighrepi is adapted for upward now of the colloidal solution during gelation. In this case, the mixing nozzle i0 is positioned at the bottom of shell H which contains a column of water-imiscible liquid heavier than water, with water thereabove, the liquid-liquid interface being again indicated at l2. Water is admitted by a pipe 28 while water carrying gelled spheroids is withdrawn by discharge line 24.

A peculiar feature of the present gel pellets is their transparency-having the appearance or clear glass beads, in many cases. This appearance is retained only when silica is predominant, the transparency being lost as content of other oxides is increased to give translucent beads.

The present pellets are extremely hard and, due to this property and their smooth surfaces, are capable of resisting losses by attrition and shock in handling for periods many times longer than the molded pellets used heretofore.

Example I A solution of sodium silicate containing grams of $10: per liter was prepared by dilutin N brand of sodium silicate (28.7% 810:, 89% No.20). This solution was mixed with a second solution containing 34.10 grams of Ill-A804): and 25.05 grams of H2804 per liter at the ratio of 1.00 volumes of the former solution to 0.780 volume of the latter. The resulting colloidal solution leaving the mixer through orifices was introduced into the top of a column of gas oil whose depth was eight feet. The globules of solution fell through the oil and gelled before passing into the layer of water located beneath the oil. The gel in the globular form was conducted out of the bottom of the column in a stream of water and on removal from the water, it was washed with petroleum naphtha to remove oil from its surface. It was then washed with water and NHQC] solution, to replace zeolitically held sodium ions by ammonium ions which are capable of being driven off as NH: gas by heat. The gel was dried slowly and uniformly at F. until shrinkage was substantially complete and the drying was continued at a gradually-increasing temperature up to 1050" F. at which temperature it was maintained for two hours. The silica-alumina gel retained its spheroidal shape during the washing and drying operations. Alternatively. the hydrogel pellets may be dried without shrinkage by replacing the original liquid phase, water, by a liquid of relatively low critical temperature, such as alcohol, heating to the critical temperature while maintaining pressure sufflcient to maintain the alcohol liquid and permitting vaporization of the alcohol at a temperature above the critical.

The time of gelation for the concentrations and proportions of reactants given above was about ten seconds, while the pH was 6.9. The gas oil employed was a fraction of Oklahoma City gas oil having a boiling range of 471 to 708 F. and a specific gravity of 0.846.

Example II This example illustrates the use of chlorobenzene as a fluid medium and the mixing of reactants at such concentrations and proportions that the gelation time was approximately twenty seconds while the pH was 6.9. Since chlorobenzene has a density of 1.101, the colloidal solution was ejected into the bottom of a ten foot column of chlorobenzene (see Fig. 4), the globules of solution rose through the fluid and gelled before passing into a layer of water contained over the chlorobenzene. The gel was washed and dried as described in Example I (the washin with petroleum naphtha was unnecessary here).

The sodium silicate solution contained 105 grams of 810: per liter (prepared from "N" brand sodium silicate) while the second solution contained 27.10 grams AMSOO: and 19.95 grams of H3504 per liter. These solutions were mixed at a ratio of 1.00 volumes of the former solution to 0.980 volume oi the latter.

Example III This example illustrates the preparation of spherically-shaped silica gel pellets and the conversion of these into a cracking catalyst. The time of gelation for the concentrations and proportions of reactants given below was about thirty seconds while the PH was 5.7.

The apparatus shown diagrammatically in Figure 1 was employed in the manufacture of the silica hydrogel. A solution of sodium silicate contaming 106.3 grams oi S102 and 33.0 grams of No.20 per liter, prepared by diluting "N" brand of sodium silicate, was metered accurately and admitted continuously to the mixing chamber by inlet I! while a metered solution of 3.90 normal hydrochloric acid was continuously fed at inlet ll. The reactant solutions were mixed at a ratio of 3.34 volumes of the sodium silicate solution to 1.00 volumes of the acid solution. The resulting colloidal solution leaving the mixer entered at the top of a nine-foot column of petroleum oil having a Viscosity of 305 Saybolt seconds and a density of 0.891. The globules of solution fell through the oil and gelled before passing into the layer of water located beneath the oil. The spherically-shaped hydrogel was conducted out of the bottom of the column II in a stream of water by means of conduits ll and 8. The bydrogel was washed with benzene to remove the film of oil and then washed with water until free of sodium chloride. The washed hydrogel was soaked overnight in a 25% solution of and then the excess solution was poured off. The spherically-shaped silica hydrogel impregnated with aluminum nitrate was dried slowly at 180 F. until shrinkage was substantially complete and the drying was continued at a gradually-increasing temperature up to 1050 F. at which temperature it was maintained for two hours. The aluminum nitrate was converted to the oxide during the heating process, and thus a silica-alumina gel catalyst in the form of spherically-shaped pellets was obtained having good activity as a cracking catalyst.

The hydrogel globules prepared in Examples I, II, and III were oi about -5 millimeters in diameter and no difllculty was encountered in drying and shrinking these to their final form. It has been found, however, that with hydrogel globules of the order of 8 or 10 millimeters in diameter considerable cracking and splitting of the globules takes place when they are dried rapidly: this may be overcome by treating the globules with boiling water or steam for at least to minutes prior to drying.

The spherical pellets of Example I have been compared by hardness tests to pellets formed in conventional manner. A comparison on cracking eiilciency shows the present pellets to have substantially the same effect as molded pellets and broken fragments. A s lica-alumina hydrogel was prepared by mixing reagents tration and in the same proportions as in Example I. This was permitted to gel as a mass in conventional manner.

The hydrogel, after being washed, was divided of the same conceninto two portions, the one part was dried. then crushed to produce fragmentary pieces of the desired size; the other portion oi the hydrogel was cast into molds and dried, thus forming small cylindrical pellets. These two forms of gel were subjected to a hardness test developed for cracking catalysts which consists of tumbling an cc. sample of material in a one-pound grease can with One )6 x 3%" Monel metal rod at 80 R. P. M. on a paint roller mill for a period of one hour, then screening the sample to determine the quantity which was powdered and broken down to a size smaller than the original. The fragmentary pieces of gel showed a breakdown of 12%, while the cylindrical pellets were broken down to the extent of 6%. The larger breakdown with the gel in the fragmentary form is probably due to the irregular shapes and to the stresses and fis sures developed during the crushing operation.

The spherically-shaped gel in Example I under the above conditions of hardness test gave no powdering nor breakdown. Continuing the test for an additional 15 hours merely scratched the surface of the spheres, thus producing only a negligible amount of fines. subjecting the gel to the hardness test for a total of eighty hours gave 0.3% of material which was smaller in size than the original. The pellets of this invention generally show losses under this test or less than 1% per hour, while the preferred pellets show losses less than 0.25% per hour.

The pellets or this invention may act as carriers for other material in the manner well known in the art.

The gel pellets of the present invention vary in size according to the degree of subdivision of the colloidal solution which is, in turn, a function of several variables, the most important beng manner of supplying the colloidal solution and surface tension at the interface between colloidal solution and the immiscible liquid to which it is supplied. Size of the pellets will also be aifected by the manner of drying, it appearing that shrinkage during drying is due to capillary action at the meniscus or the liquid phase as it retreats through the porous gel structure. Pellets as large as desired can be prepared: but for most purposes, particularly for catalytic hydrocarbon conversion, maximum sizes are about 10 millimeters in diameter. Preferably. the pellets are about 3 to 7 millimeters in diameter, while present indications are that 5 millimeter particles are of general application.

For special requirements, much smaller pellets can be formed if desired. For example, in preparing a catalyst to be utilized in a process wherein the catalyst is suspended in the reactant gases, pellets having an average diameter less than 0.1 millimeter can be produced. Nozzles with small openings are preferably used where gelation occurs in a liquid medium. Thus. any 01' the nozzles illustrated may be reduced at the outlet or fitted with a plate across the outlet having a plu rality of small holes. Small openings of this type may often give gel deposits inside the nozzle and require frequent cleaning. This eiiect is preferably avoided to a large extent by forming a colloidal solution which requires several m nutes time for gelation at room temperature and passing that sol from the mixing nozzle to a body of oil at elevated temperature. The heating of the sol globules thus accelerates gelling to obtain practical gelling times while gelatlon in the nozzle is discouraged. Such a process is illustrated by the following example.

trample W Awaterglasssolutionwaspreparedbr dilutin: 31.40 pounds of "N" brand of sodium silicate with 17.88 pounds of water. This solution contained2l2 gramsofsiozperliterandudgrams of NaaO per liter. A second solution was prepared by dissolving 387 grams of sodium aluminate in water to form ten liters of solution. These two solutions were mixed in batch form with eillcient stirring in the ratio of 100 volumes of the former to 67.8 volumes of the latter.

The sodium aluminate-sodium silicate solution, immediately after preparation, was mixed in the nozzle mixer with a 1.224 normal hydrochloric acid in equal volumes to form a colloidal solution having a pH of 5.! and a gelation time of three minutes at room temperature. The colloidal solution was extruded from the sonic mixer into the top of a column of gas oil whose depth was twelve feet and which was maintained at a temperature of 95 C. The sol globules fell through the oil and gelled before passing into the layer of water located beneath the oil. Washing and drying of the hydrogel were conducted as described in Example 1.

Example IV illustrates the preferred method of preparing pellets having diameters of less than 0.1 millimeter, however, pellets of any desired size may be prepared by this method. Colloidal solutions, prepared by the methods of this invention, having gelation times at room temperature of more than several minutes and as long as several hours may be converted into spheroidal pellets by preheating the sol for a predetermined length of time and then introducing it in the form of globules into a body of oil at an elevated temperature, wherein the so] globules gel. This process is illustrated in the following example.

Example V The sodium aluminate-sodium silicate solution prepared as described in Example IV was mixed in the nozzle mixer with a 3.780 normal hydrochloric acid solution in the ratio of 100 volumes of the former solution to 32.6 volumes of the acid solution to form a sol having a pH of 3.4 and a gelation time of two hours at room temperature. The colloidal solution leaving the mixing chamber was pumped through a preheater which consisted of a pipe twisted into a coil and immersed in a bath maintained at 70 C'. The sol remained in the preheater for 120 seconds before being introduced, in the form of globules, at the top of a column of gas oil which was twelve feet deep and was maintained at a temperature of 95 C. The globules of the colloidal solution fell through the oil and gelled before into the layer of water located beneath the oil. The hydrcgel pellets were washed and dried as described in Example I.

Small particles are also obtained by crushing the pellets to any desired size. The present gels are found to retain their high hardnesses after such crushing and their high densities are also retained. Some change in apparent density is found due to closer packing of the particles. Under conditions of commercial operation there is a substantial proportion of product which is rejected, either because of size or because of cracking of the pellets. These rejects furnish a good source of hard gel for crushing.

The pellets are generally spheroidal in shape, usually being somewhat flattened to forms approximating ellipsoids. The irregularity of the shapes and sizes under meth'ods of commercial strongly reminiscent of the in the bed of a water course; though the pellets are. lwh smaller- !"or that reason. the seems to be "rounded pellets" designating solids which are bounded substantially solely by smooth curves, and having substantially no plans or angular faces. The surfaces of the pellets, in addition to being made up of smooth curves, are usually inherently smooth themselves; being similar to a glass in smoothness and luster at surfaces resulting from formation as contrasted with fracture surfaces. The resemblance to glass is further intensified by the nature of the fracture and the power to transmit visible light. The fracture is characteristically conchoidal and the pellets are transparent to translucent, depending upon the mode or formation; 1. e., concentration and pH 01 colloidal solution, history of treatment, etc. This is in marked contrast to the molded synthetic gel pellets which are essentially chalky in appearance and physical characteristics, although a little harder than chalk.

The surfaces (both original and fracture surfaces) of the present pellets are extremely hard in view of the chemical and physical nature thereof. Precipitated silica. is normally soft and the highly porous nature of the pellets leads to an expectation that the pellets would have easily scratched surfaces. Surprisingly, the surfaces have hardnesses on the order of that of glasses. The preferred types vary in hardness from slightly less than 4 on Mohs scale to 6 and harder. Pellets are readily obtained on a commercial scale capable of scratching annealed glass such as "Pyrex." The advantages of such hardness are obvious, particularly when coupled, as in the present case, with a smooth surface. When used for catalytic conversion of hydrocarbons, for example, particles of catalytic material are either packed in a stationary bed, passed continuously as a moving column through a treating chamber or suspended in the gaseous material to be contacted. In the continuous processes, the particles are in constant motion and subjected to constant abrasion. Smooth, hard surfaces, such as those of the present pallets, resist abrasion; while the soft rough surfaces of the particles used by the prior art break down rapidly, producing undesired fines and using up the catalyst. Even in stationary bed operation, the pellets are subjected to destructive forces. The pellets must be transported to and placed in the apparatus and during operation, flowing gases and fluctuating pressures result in the motion of portions of the contact bed and by these means produce undesirable attritlon.

The strength of the pellets is extremely high. Individual particles, prepared in the manner described above, support well over 50 pounds. This is determined by placing a single pellet on an anvil and applying force directly to the upper surface of the pellet until it crushes. Individual pellet strengths in excess of pounds are preferred and strengths of 350 pounds are not unusual in normal pellets prepared as described. A contrast with molded pellets of the same chemical composition is helpful. As prepared commercially, these molded pellets crush under a weight of about 5 pounds. By molding under high pressure, it is possible to achieve a strength of about 20 pounds maximum; but pressure molding is not commercially feasible. The crushing strength or the pellets in mass is also extremely high. Normal pellets of this invention will withstand (in mass) pressures upwards of 1000 pounds per square inch and it is preferred that the mass or pellets be capable of withstanding at least 2000 pounds per square inch. Batches have been prepared of pellets which, in mass, withstand pressure of 3000 pounds per square inch or more. For purposes of comparison, it is noted that commerciallumolded silica gel catalyst in mass crushes un pressures o 500 pounds per square inch, while particles of silica gel catalyst in mass crush under pressures of 100 pounds per square inch.

The hardness and strength oi the present catalyst is further illustrated by results oi an impact test wherein catalyst is carried by an air stream through a tube to be projected against a vertical steel plate. Fines are withdrawn upwardly while catalyst 01' larger size drops into a hopper to be returned to the air stream. Fllteen hours oi recycling the catalyst in this manner produced 46% of fines from typical molded catabst while none 01' the catalysts according to this invention produced more than 5% oi! fines. The prel'erred catalysts show extremely small losses; for example, 0.1% in the case oi the catalyst of Example I.

Internally, the present gel pellets have substantially the structure 01 the original hydrogel with the liquid phase removed. The size of the pellet is, of course, reduced in normal drying and the structure is probably slightly deformed to a degree commensurate with deformation of the pellet as a whole. For all practical intents and purposes, however, the original gel structure is completely retained by the dried pellets. It is a. necessary corollary oi this fact that the finished gel pellets are uniiormly porous as contrasted with molded pellets wherein some portions are badly deformed by the molding operation to largely eliminate a portion oi the porous structure.

The apparent density of the product varies in the same direction as the crushing strength, but the strength is not simply a function of apparent density. By the term "apparent density. reference is made to weight, as compared with the volume occupied by a mass oi the particles. It is determined by weighing a fairly large volume of particles. For example, a large diameter graduated cylinder is filled to a volume calibration and the weight of. pellets determined by difference in weight of the graduate before and after filling with pellets. In general, apparent density 01 the present pellets varies between 0.5 and 1.1 grams per cc. Lighter pellet have apparent densities as low as 0.3 gram per cc. can be prepared but their hardness and crushing strength are low. Apparent densities above 0.7 gram per cc. are preferred. By comparison, molded gel catalyst usually has an apparent density around 0.55 gram per cc. ties, up to about 0.75 gram per cc. are possible with high pressure molding. An in eresting interdependence or apparent density and composition of the gel pellets has been noted. when silica-alumina gels are prepared by mixing sodium aluminate, water glass and a mineral acid, increased apparent densities permit lowering of the alumina content for equal activities. Strangely, this rule does not apply if the colloidal solution to be gelled is obtained by mixingaiumlnum sulfate and water glass to obtain a colloidal solution of the same pH, silica content and of 410 F. by

alumina content. The table below shows the strange relationship noted above. The table shows activities of a number oi Alr0sBlOa Iel catalyst pellets prepared by mixing sodium aiuminate, water glass and sulfuric acid.

Table new: ooln- A t de nsi ty or Activity catalyst Also; Hi0;

a0 01 cm as a o as a its as 10. n no a sec to so can am so as 01.5 am 18 as m. s u. an 43 an 91.0 0. sea 41 The activity" of the catalyst is a measure oi its capacity to catalyze conversion of hydrocarbons and is expressed here as the percentage conversion or Oklahoma City as oil having an A. P. I. gravity oi 35.8 and a boiling range of 471 to 708 F. to gasoline having an end point passing vapors oi the said gas oil through the catalyst at 800 l"., substantially atmosph'eric pressure and a feed rate 01' 1.5 volumes of liquid oil per volume 01 catalyst per hour.

The activity is a relative property which can be defined accurately only with respect to a speciflc conversion at specified conditions. Thus, on the basis of the defined test, suitable catalysts in general will have activities of not less than about 5%. Obviously, a 5% conversion to gasoline is not a good commercial process, but the test is not intended to indicate maximum or minimum activity; but rather to afiord a basis for comparison of catalysts. It would be extremely difiiclt to evaluate activity on any other basis. since conversion varies with nature oi the charging stock and conditions oi treatment. In general, conversion of gas oil to gasoline increases with increased temperature or pressure. A "lowactivity" catalyst usually gives reasonably good yields at more drastic conditions. A typical catalyst or low activity on the basis of the present test is a silica-alumina catalyst having an activity of 5% in the above arbitrary test. But at 900 to 950 F. conversion to gasoline on the order or 30% may be achieved with the same c rging stock. pressure and rate.

Hydrocarbon conversion catalysts should have activities of about 5% or better in the above test, while for general purposes (1. e., use over the whole range or conversion conditions) catalysts 01 at least 20% activity are desirable. It is preferred that the catalyst have an activity of not less than 40%.

Density 0! the catalyst is an important property in itself for many uses. In ny type of catalytic conversion of hydrocarbons. some of the solid catalyst is carried by the converted vapors. When using the preferred pellet catalyst of this invention as a bed, either stationary or moving, the amount of fines so carried is extremely small and may oiten be permitted to pass with the vapors for collection with residual tarry material after separation or lighter, more valuable hydrocarbons. However, if it is desired to separate fines so carried, or in processes where the catalyst is suspended in the vapors, separation is a major problem. The high densities of the preferred catalysts oi this invention permit or ready separation oi finely divided material. These pnei'erred catalysts have apparent densities in excess 01' about 0.! gram per milliliter.

Another eiiect oi density is in controlling temperatures of the catalyst mass in use. In repreheated air. means to abstract heat 'rrom this highly exothermic reaction to prevent damage to the catalyst. The more dense catalysts have a higher heat capacity per unit volume and are.thus able to absorb more heat themselves without sufferin; heat damage, thus decreasing the load on other heat-controlling means in the system.

As noted above, the present pellets are very well suited to bed-in-place operations of the type described in the patents to Eugene J. Houdry and associates. Much greater advan tages are realized. however, in continuous operation in apparatus for passing the catalyst cyclically through conversion and regeneration zones: ior example, the apparatus of Figures 5 and 6.

In Figure 5. character 80 denotes a regeneration chamber, ii a purging section, I2 a reaction chamber, 33 a second purging section, and it an elevator for catalyst particles. Regeneration chamber 30 and reaction chamber I2 are similar in construction and internal fittings and consist (referring now to 80) 01 an exterior shell 10, which may be cylindrical or rectangular in crosssection, with a convergent sealed top 95 and a convergent bottom I5, and fitted with an interior raise bottom it, which is perforated, the periorations therein being too small for the passage catalyst particles but permitting the passage of liquid or gas. Bottom 35 is fitted with pipe 81, and top 05 with pipe 38. At the top of II is a sealed ieeding device 10, which may be a star wheel as shown, an intermittently operated valve setup or other common device 01 this nature. Catalyst material introduced through 8! fills the interior of shell 30, passes down therethrough, is collected ll and is removed by a second intermittently operating device, such as star wheel II. This arrangement eilects a continuously moving stream 0! catalytic material through shell 30.. Reaction mixture, in this case air for an oxidizing regeneration, may be introduced through pipe 31, and products 01' reaction, in this case flue gas, may be removed through pipe 30. This effects a continuously flowing stream of reaction material in physical contact with the continuously flowing stream of catalytic material in shell 80. The iiow shown is countercurrent. I! desired, it may be made concurrent by reversing the functions of l! and 30, Shell 32 is similarly fitted and similarly operated. Reaction material, in this case hydrocarbons, is introduced by H, and removed by 3, catalyst movement is controlled by it and I5. Confined passaue Ii, maintained relatively full of catalyst by devices Si and H, is fitted with pipes 46 and 41, by means of which steam may be passed through the catalyst tor purging. A similar purging passage 33 lies below shell ii, is controlled by devices I! and 08, and fitted with steam pipes l9 and III for purging catalyst after reaction. From a the catalyst drops through 0 into boot 0t elevator it by which it is elevated and discharged into bin 52 above shell Ill. Elevator ll may be oi the belt and bucket type shown or or any other kind suitable ior the physical properties of the catalytic materials. Customary devices for the removal or by false bottom it and shuts lines and the addition of makeup may be inserted in the catalyst conveyor system.

Turning to Figure 8, which shows an operating setup appropriate for a conversion oi hydrocarhens, such, for example, as vapor phase cracking, charge oil is fed through pipe II by pump II to a vapor preparation unit It. Vapor preparation unit it will consist essentially of a heater, for (which purpose any of the usual terms or heater common in the art. say. a pipe still, may be used, to heat and vaporize the charge and heat it to'reaction temperature, and, it the charge used is not wholly vaporized at the reaction temperature, a vapor separator to remove unvaporized liquid residue. Vapors rrom It move through pipe ll into and through reaction chamber II, (the same as 81, Figure 5) and therein undergo catalytic reaction. Reaction products pass through pipe 59 to product purification and recovery equipment denoted by 00. Element 00 may be made up or any oi the usual fractionation. separation, and disposal devices currently in common use for handling products of cracking reactions. If desired, product fractions boiling above the desired low-boiling product may be returned to the system for retreatment, either separately or in admixture with fresh charge. Catalytic material flowing from I is purged in ii and elevated by 62 to be introduced into ll wherein it is regenerated by burning with air supplied by blower and pipe 0!, the products of regeneration being disposed of through pipe 0|, after which the regenerated catalyst is purged in 00 and returned to El.

As an example of one operation successfully conducted in such apparatus, according to the process herein disclosed, coastal gas oil with which was admixed steam to the extent 0! about 1 water (cold volumes), at a temperature of 800 F. was contacted with a catalyst of activated gel pellets prepared according to Example I at a rate of one volume or oil (cold) to four volumes or catalyst in a chamber through which the catalyst passed at such a rate that it remained in the reaction zone about 20 minutes, with the following results:

Yield of 410 E. P. gasoline (including isobutame and heavier in gas) volume, per cent 61.4 Yield 01' dry gas (lighter than isobutane) weight, per cent 4.0 Yield of coke weight, per cent 2.5 Yield of recycle siock vo1ume, per cent" 35.0

In this run the catalyst was passed through the regeneration chamber (of the same size as the reaction chamber) at the same rate, and was burned with a sufllcient volume of air to maintain above 10% C0: in the exit flue gas.

The gasoline produced was or excellent quality, high in anti-knock rating, and the recycle stock was clean, light in color, and of about the same boiling point as the charge. No high boiling, dirty, liquid cracking tar was produced. The regenerated catalyst was equal in efllclency to new catalyst, no detectable deterioration in quality being found.

When used in the apparatus of Figures 5 and 6, the present catalyst shows very low losses arising from breakdown in size 01' the smallest particles used. In general, these pellets sufier losses less than 1% per day in operations where the flow of catalyst is at a rate between about 2 and'about 4 volumesofcatalyst perhourper volume of chamber space. The preferred catalysts, having densities above about 0.7 gram per cc. and high hardness. sun'er losses less than 0.25% per day. when a plant fresh catalyst, abnormally high losses may be noted for a time if the proportion of cracked pellets is high; but cracked pellets are rapidly eliminated by breaking down and thereafter full advantage of the novel properties of the pellets is attained. Where larger pellets have been crushed and screened, substantially the same numerical values apply for losses; although low will be a little higher than for round pellets of the same density, hardness and composition. A disadvantage of such crushed and screened particles is their tendency to score the walls of reaction chambers and concurrently accumulate iron. This results in damage to equipment and catalyst since the latter is adversely afl'ected with respect to activity by iron content. Even with these disadvantages, the broken pieces are better than molded catalyst (or the reasons discussed above, but the spheroidal unbroken pellets are. of course, regarded as preferable.

A process of the type wherein catalyst is suspended in reactant gases may be performed in the apparatus of Figures 7 and 8. Such a plant includes two chambers, namely, a reactor II and a regenerator ll. Catalyst is suspended in a preheated charging stock in inlet 12 by being supplied to the inlet from a continuous feeder such as screw conveyor II. For this use, the catalyst must be at small size, usually about 80 mesh or finer, in order that it will remain suspended in the gaseous streams. The charge stock supplied as preheated vapor to inlet 12 is advantageously prepared in substantially the manner described in connection with Figure 6. The hydrocarbon vapors pass through tubes I4 in the reactor ll wherein the desired conversion, for example, cracking to gasoline, is accomplished in the presence of the suspended catalyst. The treated vapors, still carrying suspended catalyst, are passed by line H to cyclone separator I8 wherein the suspended catalyst is removed and the products of the reaction are passed by outlet 18 to suitable separation and recovery equipment as in Figure 6.

The separated catalyst, which is now contaminated by a carbonaceous deposit, is transferred by pipe II to hopper II, from which it is supplied by e II to conveyor II. The passage I! may serve as a purging zone to remove vaporizable hydrocarbons from the catalyst before contact with oxidizing gases for regeneration of the catalyst. This is accomplished by steam or other inert gas through the catalyst from inlet 82 to outlet 8|.

Preheated air is supplied to inlet '3 and the spent catalyst from conveyor .II is suspended therein for regeneration in tubes as of regenerator ll. Regenerated catalyst suspended in hot regeneration fume passes by line II to cyclone separator 86 from which are withdrawn regeneration fume by outlet I1 and hot regenerated catalyst to flow through pipe 8| to hopper 88 from which it is again supplied to conveyor ll by passage 90 and thence to the reactor inlet 12. Purg lnginpassage sllmaybebysteampassedinat II and withdrawn by ll. Since reactor II and regenerator H are 01' substantially similar construction, detailed description of one will sufllce for both.

Regenerator II is eq ipped with a long tubular is charged with or a llmilar as me means defined conducting material, which coils case to give a suiiiclent length of travel to catalyst for P per regenerating conso that when the catalyst leaves regenerator l-l it is fully regenerated. For temexchange medium.

Asshown, coil II c atubebundlecom- Thus tubes are mounted aroimdacentralpassage a whichhasbothof its ends open to the interior of the chamber and thus permits circulation of the liquid heat exchange medium therethrough. The circulation of the heat exchange medium up through passage II and back down around the tubes is efiected by means of ejector impeller pump as. located just above the top opening of passage II. The shaft ofimpeller Ilextendsupthroughthetopcover plate of the regenerator and is rotated by siltable means (not shown).

The temperature of the circulating heat exchange medium may be controlled by a suitable heating or cooling means provided around the interior or exterior of the chamber II. It is to be understood that, if desired, the temperature control and circulation of heat exchange medium obtained by other means, such as, tor example, circulating the medium through an exterior circuit containing a pump and heater or cooler.

For economical reasons. the catalyst'passing from each citse to the other case should not be permitted to cool down to atmospheric temperature, but rather should be maintained in a heated tionisobtainedinthatthneandspaceinthe case are not required for merely heating the catalyst up to the desired treating temperature, or, at least, in heating the catalyst all the way from atmospheric temperature to the treating temperature. In some operations, it may be iound desirable or necessary to place catalyst surge tanks or the like in the catalyst new lines in order to give greater flexibility to the timing of the operations, If advisable in such operations, means for heating the catalyst at these stases may be provided so that it retains a heated condition.

In order to obtain proper temperature control, the heat exchange medium must be adiusted to a proper temperature for extracting or adding the necessary heat. Moreover, the heat exchange medium must be circulated in suilicient amount in close indirect heat exchange with every catalyst particle and then cooled or heated to readjust its temperature by means extraneoim of the reaction heat before the medium's temperature reaches an undesired value. heat exchange medium in this embodiment continuously controls the temperature of the zone making immediate compensations for temperature changes whereby no deleterious temperatures occur.

When the operation is first started, the heat exchange medium may add some heat to help initiate combustion or at least the medium should not be at such a low temperature as to prevent combustion initiation. After is startbroken catalysts of the prior art yield relatively ed, operations by this means are so eiiicient that large quantities oi fines of smaller size than the heat is extracted from the exothermic regeneration reaction, i. e., in the usual case such as regeneration of cracking catalysts by burning.

The liquid heat exchange medium to be used is preferably one which at the temperatures encountered is possessed of a low vapor pressure, a high specific heat, a suitable viscosity and is not corrosive to the usual metals and other materials which may be used in construction of the apparatus. Many normally solid materials in their fused state form excellent heat exchange mediums such as fused salts and fused metals and alloys. In the regeneration of cracking catalvsts, we prefer the use of fused salts. A particularly preferable mixture of this kind is a mixture of the alkali metal salts of nitric and nitrous acids. In certain cases, suitable liquid heat exchange mediums might be found which have a boiling point around the desired operating temperature. in which case, the heat exchange medium would be kept predominantly in the liquid state but might undergo some transition whereby advantage could be taken of its heat of vaporization or condensation.

In the preferred practice, the heat exchange medium is maintained at substantially the temperature of the treatment being controlled, e. g., above the minimum temperature at which proper reaction is obtained and below the minimum temperature at which deleterious results occur, such as damage to the catalyst. Such practice may be carried out very effectively when the heat exchange medium is a liquid and has a relatively high specific heat. The structure of the amratus is such that heat exchange medium is brought within close proximity to every granule in the apparatus. Hence, considerable fluctuations in temperature in either direction can be compensated by the liquid heat exchange medium without substantially altering its temperature and suitable cooling or heating of the heat exchange medium in its circuit maintains the liquid at the treating temperature.

The air rate should be sufficient to freely flow and carry the catalyst particles. It is preferable to use the minimum velocity which will accomplish this result so that the longest possible contact time will be aflorded for a given length of apparatus.

Close control of temperatures in both reactor and regenerator may be achieved by full heat exchange as shown in both chambers. The conversion reaction is usually slightly endothermic and the two chambers may be made to balance each other to some extent by use of a common external circuit for heat exchange medium. However, the abmrption of heat in conversion is much less than the heat evolved in regeneration. If desired, heat exchange in the reactor Ill may be dispensed with and temperature control maintained by preheating of hydrocarbon vapors and catalyst. In such case, a simple enlarged chamber may be used as the reactor.

Continuous catalytic operation of this type involves some disadvantages. Complete separation of a gas from a solid suspended therein is difficult to accomplish at the rates of gas flow essential to commercial practice. However, the present high density particles separate more readily than do the previously used low density catalysts. Another important feature of the catalyst for catalysis in suspension is the hardness and resistance to mechanical breakdown. The soft, easily particles supplied to the apparatus. These are very difficult to separate from the gases and catalyst loss is accordingly hi h. The present catalyst retains its size characteristics in use to a large extent and losses are therefore minimised. There is, of course, a tendency of the suspended catalyst to act as an abrasive in a manner analogong to sand blasting. This not only wears away the equipment, but also causes the catalyst to take up foreign matter detrimental to its catalytic properties. Iron from steel members and non-metallic matter from concrete and the like all affect the catalyst activity deleteriously. It is therefore preferred that my spheroidal particles be used in suspended catalyst operation. This provides for the first time an adsorptive body capable of suspension in gases which has smooth hard surfaces whereby the catalyst breakdown is greatly reduced, blasting oi. equipment is largely eliminated and contamination of catalyst cut down to a practical minimum.

1 claim:

1. In a process for the manufacture of valuable hydrocarbon products by conversion of heavier hydrocarbon reactants in contact with an inorganic synthetic gel conversion catalyst containing silica and a metal oxide, the improvement which comprises contacting said hydrocarbon reactants at conversion conditions of temperature and pressure with hard homogeneous porous dried particles of said gel bounded by smooth hard glossy surfaces consisting substantially of smooth curves and characterized by a high resistance to attrition 1058, said particles having been produced by a process which comprises forming a hydrosol of inorganic oxide including silica and said metal oxide characterized by an inherent capacity to set to a hydrogel upon the lapse of a suitable period of time without addition to or subtraction from said gel of any substance, admitting said sol in the form of separate globules to a body of a fluid medium substantially immiscible with water in which said globules assume spheroidal shape due to our face tension at the interface between said sol and said medium, retaining said spheroidal globules in said medium until gelation occurs thus forming spheroids of hydrogel, effecting retention in said sol of substantially all the constituents of said 501 until gelation occurs and drying the hydrogei spheroids.

2. In a process for the manufacture of valuable hydrocarbon products by conversion of heavier hydrocarbon reactants in contact with an inorganic synthetic gel conversion catalyst containing silica and alumina, the improvement which comprises contacting said hydrocarbons at conversion conditions of temperature and pressure with hard homogeneous porous dried particles of said gel bounded by smooth hard glossy surfaces consisting substantially of smooth curves and characterized by a. high resistance to attrition loss, said particles having been produced by a process which comprises forming a hydrosol of inorganic oxide including silica and alumina characterized by an inherent capacity to set to a hydrogel upon the lapse of a suitable period of time without addition to or subtraction from said gel of any substance, admitting said sol in the form of separate globules to a body of a fluid medium substantially immiscible with water in which said globules assume spheroidal shape due to surface tension at the interface between said sol and said medium, retaining said spheroidal globules in said medium until gelation occurs thus forming spheroids of hydrogel, eil'ecting retention in said sol of substantially all the constituents of said sol until gelation occurs and rying the hydrosel spheroids.

3. In a process for the manufacture of valuble hydrocarbon products by conversion oi heavier hydrocarbon reactants in contact with an inorganic synthetic gel conversion catalyst containing silica and a metal oxide, the improvement which comprises contacting said. hydrocarbon re. actants at conversion conditions of temperature and pressure with hard homogeneous porous dried particles of said gel bounded by smooth hard glossy surfaces substantially of smooth curves and'characterised by a high resistance to attrition loss, said particles having beenrproduced by a process which comprises forming a hydrosol oi inorganic oxide including silica and said anetal oxide characterised by an inherent capacitytosettoahydrodelllp nthelapse of a suitable period of time without addition to or subtraction from said gel of any substance. admitting said sol in the form or separate globules to a body of a liquid medium substantially immiscible with water in which said globules assume spheroidal shape due to surface tension at the interface between said sol and said medium, retaining said spheroidal globules in said medium untfl gelation occurs thus forming spheroids of hydrogel, eflecting retention in said sol or substantially all the constituents of said sol until gelation occurs and drying the bydrogel spheroids.

4. In a process for the manufacture of valuable hydrocarbon products by conversion of heavier hydrocarbon reactants in contact with an inorganic synthetic gel conversion catalyst containing silica and alumina, the improvement which comprises contacting said hydrocarbon reactants at conversion conditions or temperature and pressure with hard homogeneous porous dried particles of said gel bounded by smooth hard glossy suriaces consisting substantially of smooth curves and characterized by a high resistance to attrition loss, said particles having been produced by a process which comprises forming a hydrosol of inorganic oxide including silica and alumina characterized by an inherent capaci y to set to a hydrogel upon the lapse of a suitable period of time without addition to or subtraction from said gel oi any substance, admitting said sol in the form of separate globules to a body or a liquid medium substantially immiscible with wafer in which said globules assume spheroidal shape due to surface tension at the interface between said sol and said medium, retaining said spheroidal globules in said medium until gelation occurs thus forming spheroids of hydrogel, eilecting retention in said sol of substantially all the constituents of said sol until gelation occurs and drying the hydrogel spheroids.

5. In a process for the manufacture or valuable hydrocarbon products by conversion of heavier hydrocarbon reactants in contact with an inorganic synthetic gel conversion catalyst containing silica and a metal oxide, the improvement which comprises contacting said hydrocarbon reactants at conversion conditions of temperature and pressure with hard homogeneous porous dried particles of said gel bounded by smooth hard glossy surfaces consisting substantially of smooth curves and characterized by a high resistance to attrition loss, said particles having been produced by a process which comprises forming a hydnosol of inorganic oxide including silica and said metal oxide characterized by an inherent capacity to set to a hydrogel upon the lapse of a suitable period 4 of time without addition to or subtraction from said gel of any substance, admitting said sol in the form oi separate globules to a body of a fluid medium substantially immiscible with water in which said globules assume spheroidal shape due to surface tension at the interface between said sol and said medium, retaining said spheroidal globules in said medium until gelation occurs thus forming spheroids or hydrogel, effecting retention in said sol of substantially all the constitutents of said sol until gelation occurs, washing the hydrogel spheroids with water, base exchanging the washed spheroids to remove alkali metals therefrom and drying the hydrogel spheroids.

8. In a process for the manufacture oi valuable ydrocarbon products by conversion 0! heavier hydrocarbon reactants in contact with an inorganic synthetic gel conversion catalyst containing silica and alumina, the improvement which comprises contacting said hydrocarbons at conversion conditions of temperature and pressure with hard homogeneous porous dried particles 'oi' said gel bounded by smooth hard gloss surfaces consisting substantially of smooth curves and characterized by a high resistance to attrition low, said particles having been produced by a process which comprises forming a hydrosol of inorganic oxide including silica and alumina characterised by an inherent capacity to set to a hydrogel upon the lapse of a suitable period of time without addition to or subtraction from said gel of any substance, admitting said sol in the form of parate globules to a body or a fluid medium substantially immiscible with water in which said globules assume spheroidal shape due to surface tension at the interface between said sol and said medium. retaining said spheroidal globules in said medium until gelation occurs thus forming spheroids oi hydrogel, eil'ecting retention in said sol of substantially all the constituents of said sol until gelation occurs, washing the hydrogel spheroids with water, base exchanging the washed spheroids to remove alkali metals therefrom and drying the hydrogel spheroids.

7. In a Process for the manufacture of valuable hydrocarbon products by conversion or heavier hydrocarbon reactants in contact with an inorganic synthetic gel conversion catalyst containing silica and a metal oxide, the improvement which comprises contacting said hydrocarbon reactants at conversion conditions of temperature and pressure with hard homogeneous porous dried particles of said so] bounded by smooth hard glossy surfaces consisting substantially of smooth curves and characterized by a high resistance to attrition loss, said particles having been produced by a process which comprises forming a hydrosol of inorganic oxide including silica and said metal oxide characterized by an inherent capacity to set to a hydrogel upon the lapse of a suitable period of time without addition to or subtraction from said gel or any substance, admitting said sol in the form of separate globules to a body of a liquid medium substantially immiscible with water in which said globules assume spheroidal shape due to surface tension at the interface between said so] and said medium. retaining said spheroidal globules in said medium until gelation occurs thus forming spheroids of hydrogel, eii'ecting retention in said sol of substantially all the constituents oi said sol until gelation occurs. washing the hydrogel spheroids with water, base exchanging the zanic synthetic gel conversion catalyst containing silica and alumina, the improvement which comprises contacting said hydrocarbon reactants at conversion conditions of temperature and pressure the lapse oi a suitable period of time without addition to or subtraction from said gel or any substance, admitting said sol in the form 01' separate globules to a body of a liquid medium substantially immiscible with water in which said globules assume spheroidal shape due to surface tension at the interface between said sol and said medium, retaining said spheroidal globules in said medium until selation occurs thus forming sphewith hard homogeneous porous dried particles of 10 roids oi hydrosel, effecting retention in said sol of said sel bounded by smooth hard glossy surfaces substantially all the constitutents of said $01 until consisting substantially of smooth curves and gelation occurs washing the hydrogel spheroids charaeterizedbyahigh resistancew attrition loss, with water, base exchansins the washed sphesaid particles having been produced by a process roids with water, base exchanging the washed which comprises iorming a hydrosol of inorganic is spheroids to remove alkali metals therefrom and oxide including silica and alumina characterized by an inherent capacity to set to a hydrosel upon CERTIFICATE OF EORRECTI 0N.

HILTON H. HARISIC.

drying the hydrosel BDheroids.

MILTON M. MAR-151C.

- September 18, 19ll5.

It is hereby certified that error appears in the printed specification of. the above numbered patent requiring correction as follows: Page 6, first col'immwlline 57, for 'hnve read "having-4 page 10, first coimnn, line 5,

clain 5, for 'valuhle" read ,--valuable--; line 9, for 'aiilce." read --silicc--; and second dfol'mnn, line 10, claim 5, forl'or" before "hydrogel" read --of--; page 11, second column, lines 11+ and 15, claim 8 strilne out the words "with water, base exchanging the washed spheroids"; and that the said Letters i'atent should be read with this correction therein that the same may cond'om to. the record or the case. in me liitent Office.

si ned and sealed an. 9m day or A ril, A. a. mile.

ileslie Frazer (Seal) first Assistant Cunni ssioner of Patents.

zanic synthetic gel conversion catalyst containing silica and alumina, the improvement which comprises contacting said hydrocarbon reactants at conversion conditions of temperature and pressure the lapse oi a suitable period of time without addition to or subtraction from said gel or any substance, admitting said sol in the form 01' separate globules to a body of a liquid medium substantially immiscible with water in which said globules assume spheroidal shape due to surface tension at the interface between said sol and said medium, retaining said spheroidal globules in said medium until selation occurs thus forming sphewith hard homogeneous porous dried particles of 10 roids oi hydrosel, effecting retention in said sol of said sel bounded by smooth hard glossy surfaces substantially all the constitutents of said $01 until consisting substantially of smooth curves and gelation occurs washing the hydrogel spheroids charaeterizedbyahigh resistancew attrition loss, with water, base exchansins the washed sphesaid particles having been produced by a process roids with water, base exchanging the washed which comprises iorming a hydrosol of inorganic is spheroids to remove alkali metals therefrom and oxide including silica and alumina characterized by an inherent capacity to set to a hydrosel upon CERTIFICATE OF EORRECTI 0N.

HILTON H. HARISIC.

drying the hydrosel BDheroids.

MILTON M. MAR-151C.

- September 18, 19ll5.

It is hereby certified that error appears in the printed specification of. the above numbered patent requiring correction as follows: Page 6, first col'immwlline 57, for 'hnve read "having-4 page 10, first coimnn, line 5,

clain 5, for 'valuhle" read ,--valuable--; line 9, for 'aiilce." read --silicc--; and second dfol'mnn, line 10, claim 5, forl'or" before "hydrogel" read --of--; page 11, second column, lines 11+ and 15, claim 8 strilne out the words "with water, base exchanging the washed spheroids"; and that the said Letters i'atent should be read with this correction therein that the same may cond'om to. the record or the case. in me liitent Office.

si ned and sealed an. 9m day or A ril, A. a. mile.

ileslie Frazer (Seal) first Assistant Cunni ssioner of Patents. 

